Question

Design a finite state machine for a traffic light at the intersection of north-south traffic and east-west traffic. The light can be red, green or yellow. Assume a 30 second clock. Assume that the light will change only if a car is coming in the other direction. If cars are in both north-south and east-west, the light will change from one direction to the other. What are the machine states? What are the inputs? What are the outputs? Draw state table Draw state diagram Develop the circuit for the NEXT STATE using combinational logic (can use a MUX). You do not need to draw the circuit only the equations. If you make any other assumptions, that do not contradict the given assumptions, please specify

Answer 1

Points assumed :-

• Assum a 30 second clock.
• Assume that the light will change only if the car is cming from other direction .
• Assume the light will not go red until it becomes yellow and similarly lights will not turn greeen until it is red.

carew carns reset carew carew carns SO S1 S2 Lns red Lew green S3 Lns g Lew red Ins yellow Lew red Lns red Lew yellow carns state diagram

State table Current state Input Next state carns carew SO S1 S2 S1 S2 S2 S3 0 S2 S3 S4

INPUT STATES :- input states are those in which car comes and state changes to anther. and all states other than green light state are all input states .(i.e. s1 and s2)

output states :- output states are all those states in which light turns to green (i.e. s0 and s3 )